<html>
<head><meta charset="utf-8"><title>overhead · t-compiler/wg-self-profile · Zulip Chat Archive</title></head>
<h2>Stream: <a href="https://rust-lang.github.io/zulip_archive/stream/187831-t-compiler/wg-self-profile/index.html">t-compiler/wg-self-profile</a></h2>
<h3>Topic: <a href="https://rust-lang.github.io/zulip_archive/stream/187831-t-compiler/wg-self-profile/topic/overhead.html">overhead</a></h3>

<hr>

<base href="https://rust-lang.zulipchat.com">

<head><link href="https://rust-lang.github.io/zulip_archive/style.css" rel="stylesheet"></head>

<a name="165106861"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/187831-t-compiler/wg-self-profile/topic/overhead/near/165106861" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/187831-t-compiler/wg-self-profile/topic/overhead.html#165106861">(May 07 2019 at 20:17)</a>:</h4>
<p>Also, <span class="user-mention" data-user-id="124287">@mw</span> and I were talking earlier and discussing the "perf integration". Do we have any idea of "instruction count ovehead" that enabling this feature brings? Memory overhead, I understand, is substantial.</p>



<a name="165106975"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/187831-t-compiler/wg-self-profile/topic/overhead/near/165106975" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Wesley Wiser <a href="https://rust-lang.github.io/zulip_archive/stream/187831-t-compiler/wg-self-profile/topic/overhead.html#165106975">(May 07 2019 at 20:18)</a>:</h4>
<p>mw had a PR where we measured it</p>



<a name="165106985"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/187831-t-compiler/wg-self-profile/topic/overhead/near/165106985" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Wesley Wiser <a href="https://rust-lang.github.io/zulip_archive/stream/187831-t-compiler/wg-self-profile/topic/overhead.html#165106985">(May 07 2019 at 20:18)</a>:</h4>
<p>/me looking</p>



<a name="165107147"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/187831-t-compiler/wg-self-profile/topic/overhead/near/165107147" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Wesley Wiser <a href="https://rust-lang.github.io/zulip_archive/stream/187831-t-compiler/wg-self-profile/topic/overhead.html#165107147">(May 07 2019 at 20:20)</a>:</h4>
<p><a href="https://perf.rust-lang.org/compare.html?start=e4e032a0ae82d7db4f99872ff98626af2941c4a5&amp;end=5539376de500270af54c7741ff8075316d950caf" target="_blank" title="https://perf.rust-lang.org/compare.html?start=e4e032a0ae82d7db4f99872ff98626af2941c4a5&amp;end=5539376de500270af54c7741ff8075316d950caf">https://perf.rust-lang.org/compare.html?start=e4e032a0ae82d7db4f99872ff98626af2941c4a5&amp;end=5539376de500270af54c7741ff8075316d950caf</a></p>



<a name="165107226"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/187831-t-compiler/wg-self-profile/topic/overhead/near/165107226" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/187831-t-compiler/wg-self-profile/topic/overhead.html#165107226">(May 07 2019 at 20:21)</a>:</h4>
<p>Ah, hmm, not <em>that</em> bad.</p>



<a name="165108355"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/187831-t-compiler/wg-self-profile/topic/overhead/near/165108355" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/187831-t-compiler/wg-self-profile/topic/overhead.html#165108355">(May 07 2019 at 20:32)</a>:</h4>
<p>My opinion here is that we should probably do it :) at least, it seems so <em>super</em> useful to be able to get this data readily</p>



<a name="165108380"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/187831-t-compiler/wg-self-profile/topic/overhead/near/165108380" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/187831-t-compiler/wg-self-profile/topic/overhead.html#165108380">(May 07 2019 at 20:33)</a>:</h4>
<p>but I guess it depends a bit on how <em>consistent</em> the overheads are etc</p>



<a name="165108394"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/187831-t-compiler/wg-self-profile/topic/overhead/near/165108394" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/187831-t-compiler/wg-self-profile/topic/overhead.html#165108394">(May 07 2019 at 20:33)</a>:</h4>
<p>(I'm doing some local perf runs and already finding the results very interesting)</p>



<a name="165108739"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/187831-t-compiler/wg-self-profile/topic/overhead/near/165108739" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/187831-t-compiler/wg-self-profile/topic/overhead.html#165108739">(May 07 2019 at 20:36)</a>:</h4>
<p>also, reasonably consistent run to run</p>



<a name="165108751"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/187831-t-compiler/wg-self-profile/topic/overhead/near/165108751" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/187831-t-compiler/wg-self-profile/topic/overhead.html#165108751">(May 07 2019 at 20:37)</a>:</h4>
<p>some small-ish variation</p>



<a name="165108909"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/187831-t-compiler/wg-self-profile/topic/overhead/near/165108909" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Wesley Wiser <a href="https://rust-lang.github.io/zulip_archive/stream/187831-t-compiler/wg-self-profile/topic/overhead.html#165108909">(May 07 2019 at 20:38)</a>:</h4>
<p>That's good to hear! I don't think we currently have any data about how much variability it introduces.</p>



<hr><p>Last updated: Aug 07 2021 at 22:04 UTC</p>
</html>